[ Thanks to shantanu for this link.
]
“Though this does trick for me but there are other helpful
suggestions also which you can try/check to speed up your
backup/restore process, few are as follows:“Increase value of key_buffer_size variable in my.cnf to 20-25%
of available RAM as mentioned above. Be aware that, if you make the
value too large like setting more than 50% of total RAM, your
machine may start to page and become extremely slow. This is
because MySQL relies on the operating system to perform file system
caching for data reads, so you must leave some room for the file
system cache. Anyhow, remember that on 32 bit system, the maximum
value key_buffer_size can take is 4gb only and setting any greater
might crash your MySQL server.”